Alcohol consumption again linked to breast cancer risk

SAN DIEGO — Epidemiological data from two studies presented at the 2008 Annual Meeting of the American Association for Cancer Research have provided further evidence that alcohol may increase postmenopausal women’s risk for breast cancer.

“We found that regular consumption of alcohol can lead to an increased relative risk of breast cancer, specifically estrogen receptor/progesterone receptor-positive types of breast cancer,” Jasmine Q. Lew, a fourth-year medical student at the University of Chicago, told HemOnc Today.

In fact, compared to women who did not drink, women who had three or more glasses of alcohol daily had as high as a 51% increased risk of ER/PR-positive breast cancer.

Lew and colleagues analyzed 184,418 postmenopausal women from the NIH-AARP Diet and Health Study. During seven years of follow-up, researchers identified 1,641 ER/PR-positive cases of invasive breast cancer.

An increasing number of drinks consumed daily correlated with an increasing relative risk for breast cancer. The increased risk was found across different types of alcohol.

ER/PR-positive breast cancers demonstrated a stronger association with alcohol than the overall group. Associations between alcohol consumption and other cancers that were either positive or negative for ER or PR were not statistically significant.

Alcohol dehydrogenase genes

In a second study, researchers further examined the association between breast cancer risk and alcohol consumption by evaluating specific variations within two genes involved with alcohol metabolism, ADH1B and ADH1C.

“We found a significant association between two sequence variations in alcohol dehydrogenase genes and alcohol drinking and breast cancer,” Catalin Marian, MD, PhD, a research instructor of cancer genetics and epidemiology at Georgetown University, told HemOnc Today.

Marian and colleagues analyzed DNA from 991 women with primary histologically confirmed breast cancer from the Western New York Exposure and Breast Cancer Study and 1,698 age- and race-matched, healthy controls.

“Our results suggest that the presence of a sequence variation in the ADH1B gene may increase the chance of breast cancer by almost twofold in postmenopausal drinking women,” Marian said. “Moreover, the presence of another variation in ADH1C confirms a protecting effect, lowering the chance of breast cancer regardless of the menopausal status, but protection is lost with increasing alcohol consumption.”

Although they found an association between sequence variation in alcohol dehydrogenase genes, alcohol drinking and breast cancer, the researchers stressed that no conclusion can be made about the causal relationship between these factors and breast cancer risk. – by Leah Lawrence

For more information:

Lew JQ. #4168.

Marian C. #5814. Both presented at: the 2008 Annual Meeting of the American Association for Cancer Research; April 12-16, 2008; San Diego.